CN108432075B

CN108432075B - Motor starter comprising protection and monitoring functions

Info

Publication number: CN108432075B
Application number: CN201780005719.6A
Authority: CN
Inventors: W·梅德
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2016-01-28
Filing date: 2017-01-27
Publication date: 2020-08-14
Anticipated expiration: 2037-01-27
Also published as: WO2017129743A1; US20190036327A1; CN108432075A; US10778000B2; DE102016101553A1; EP3408907A1

Abstract

The present invention relates to a motor starter (10) comprising: a main switch (1) configured as power semiconductor, the main switch (1) forming a semiconductor contactor and having at least one semiconductor switch for switching a phase of a total power supply of motor windings, wherein a first connection of each semiconductor switch is connected to a corresponding first total current contact (L1 to L3) of the motor starter (10); an auxiliary switch (2) configured as a semiconductor switch and connected between at least one pair of auxiliary contacts (11, 12, 13, 14) of the motor-starter; -an electronic transducer unit (3) for measuring the current of the phase of the mains supply, the electronic transducer unit (3) being connected between the second connection of each semiconductor switch of the mains switch (1) and a corresponding second mains supply contact (T1 to T3) of the motor-starter (10); and an electronic control unit (4) for the main switch (1) and the auxiliary switch (2), the electronic control unit (4) being supplied with power via control contacts (a1, a2) of the motor starter (10) and the measurement signal of the transducer unit (3) being fed to the electronic control unit (4), and the electronic control unit (4) being configured to control the main switch (1) and/or the auxiliary switch (2) as a function of the power supply via the control contacts (a1, a2) and/or as a function of the measurement signal.

Description

Motor starter comprising protection and monitoring functions

Technical Field

The present invention relates to a motor-starter for an electric motor having protection and monitoring functions without the need for mechanical components to deactivate the overall and auxiliary circuits.

Background

German laid-open application DE 4335965 a1 describes a combined motor starter with a mains switch on the mains side and a series-connected contactor on the load side and an electronic unit for measurement, control and monitoring. Both switching devices have a mechanical contact system and the electronic unit has an electronic release for motor protection and short-circuit protection. Due to the electronic release of the electronic unit, conventional release devices, such as bimetallic relays and snap-action release devices, may be replaced and complex designs for facilitating the release of short circuit currents may be avoided. In addition, electronic overload monitoring allows for a wide range of adjustments and releases of the electronic release device.

A three-phase motor starter is described in german published application DE 102013111954 a 1. The motor starter is realized by means of a contactor with mechanical contacts and a plug-in module with a semiconductor switch. The module serves to reduce the extremely high loading of the mechanical switching contacts of the contactor due to the high starting currents which occur in particular when the motor is started. For this purpose, the semiconductor switches of the plug-in modules are connected in parallel to the switching contacts by means of corresponding controls during the activation and deactivation process of the contactor, so that the switching contacts can be switched almost without being energized, thus being subjected to a reduced load. The plug-in module may have an integrated motor protection circuit breaker with release electronics and one current transformer per phase. Based on the output signal of the current transformer, the release electronics control the deactivation of the supply of power to the motor and in particular effect the deactivation of the supply of power to the motor in case of an excess of current.

According to german laid-open application DE 102009012942 a1, a motor starter designed for use as a ventilator control is known, which has semiconductor switches for switching the phases of a three-phase mains supply of the motor windings and a microcontroller as an electronic control unit for the semiconductor switches. In addition, there are transducers for two of the three phases of the three-phase mains supply, whose current measurement signals are fed to a microcontroller which controls the mains switches on the basis of the signals, thus enabling the implementation of a motor protection function.

German laid-open application DE 19742916 a1 teaches a control for an electric motor, in particular integrated in a movable and/or manually operated machine, such as a blender, an electric drill, a grinder, etc. The control has a semiconductor switch as a master switch and an overload protection function for the electric motor, which is based on a measured value of the current consumption of the electric motor. In addition, the specific operating conditions of the motor can be adjusted by means of potentiometers and button bars.

A semiconductor-based motor starter with a reverse function is known from german laid-open application DE 10003692 a 1.

Disclosure of Invention

The problem addressed by the present invention is to propose an improved motor starter.

The idea on which the invention is based is to form a complete motor starter that can be implemented without mechanical components. According to the invention, the solid-state contactors (semiconductor contactors) configured to form the main switches of the power semiconductors are built together with motor protection relays, which are combined in a housing together with control and monitoring electronics for the solid-state contactors and the motor protection relays. In addition, an auxiliary switch configured as a semiconductor switch and connected between at least one pair of auxiliary contacts of a motor starter is provided.

An embodiment of the present invention relates to a motor starter including: a main switch configured as a power semiconductor, the main switch forming a semiconductor contactor and having at least one semiconductor switch for switching a phase of a main power supply of the motor windings, wherein a first connection of each semiconductor switch is connected to a corresponding first total current contact of the motor starter; an auxiliary switch configured as a semiconductor switch and connected between at least one pair of auxiliary contacts of the motor starter; an electronic transducer unit for measuring the current of a phase of the mains supply, said electronic transducer unit being connected between the second connection of each semiconductor switch of the mains switch and a corresponding second mains supply contact of the motor starter; and an electronic control unit for the main switch and the auxiliary switch, which electronic control unit is supplied with power via the control contacts of the motor starter and to which the measuring signals of the transducer unit are fed, and which electronic control unit is configured to control the main switch and/or the auxiliary switch in dependence on the power supply via the control contacts and/or in dependence on the measuring signals. Due to the completely electronic design of such a motor starter, electronic switching and protection of the motor controls in the device can be achieved.

The motor starter can have an electronic messaging unit which is controlled by the control unit and is designed to generate messages relating to the state of the motor starter optically and/or acoustically. For example, the messaging unit can control multicolored LEDs (light emitting diodes), by means of which the different states of the motor starter can be signaled optically by different colors and/or blinks.

The electric motor-starter can also have an electronic parameterization unit which is designed to specify at least one parameter of the electronic control unit. The electronic parameterization unit can be designed to specify at least one of the following parameters as a parameter of the electronic control unit: nominal current of the motor; an inactive category of overload release of the power supply of the motor; the behavior after overload release, in particular automatic or manual reactivation. For example, a potentiometer or switch, such as a rotary or toggle switch, may be provided for setting the parameters.

The electronic transducer unit may have a current transducer and/or a hall sensor and/or other suitable measuring means for measuring the current of the phases of the mains supply.

The electronic control unit may be designed to adjust the nominal voltage rate of the motor starter based on the supply voltage applied at the control contacts. Thus, a motor-starter having a common input voltage range can be realized.

The master switch configured as a power semiconductor may have a plurality of semiconductor switches interconnected as a reversible starter. The main switch configured as a power semiconductor can also be designed as a dc starter with semiconductor switches for at least one phase of the total power supply for the motor windings. In particular, the main switch configured as a power semiconductor can be designed as a dc starter with one semiconductor switch for each phase of the total power supply of the motor windings.

In addition, the motor starter can have an interface by means of which process data are read out of the motor starter and transmitted to a control center and/or data can be received, in particular parameters of an electronic control unit.

In order to allow a compact design of the motor starter, the electronic components of the motor starter may be arranged and wired jointly on a carrier element, for example a circuit board, or on a plurality of carrier elements wired together. A plurality of carrier elements wired together may for example be arranged in a stacked manner in order to allow a compact design.

Drawings

Other advantages and potential applications of the present invention follow from the following description in conjunction with the embodiments shown in the drawings.

The terms used in the following list of reference numerals and associated reference numerals are used in the description, claims, abstract and drawings.

FIG. 1 illustrates a block diagram of an embodiment of an electronic DC motor starter with motor protection according to the present invention;

FIG. 2 illustrates a block diagram of an embodiment of an electronic reversible motor starter with motor protection according to the present invention;

FIG. 3 illustrates an embodiment of a switch and transducer for an electronic reversible motor starter according to the present invention;

FIG. 4 illustrates an embodiment of a switch and transducer for an electronic DC motor starter according to the present invention in which all current paths are switchable; and is

Fig. 5 shows an embodiment of a switch and a transducer for an electronic dc motor starter according to the invention, wherein two of the three current paths are switchable.

In the following description, similar, functionally similar and functionally connected elements may be provided with the same reference numerals. Absolute values are merely exemplary indications and should not be understood to have a limiting effect on the present invention.

Detailed Description

FIG. 1 shows a block diagram of a three-phase electronic DC motor starter 10 with conventional connecting contacts:

11 to 12: auxiliary contact pair (break contact)

13 to 14: auxiliary contact pair (make contact)

L1 to L3: (first) Main Power contact on Power side

T1 to T3: (second) main power supply contact on load side

A1 to A2: control contact (coil connection)

The motor-starter 10 is constructed entirely of electronic components that are arranged and wired on a circuit board that serves as a carrier. The circuit board is accommodated in a housing of the motor starter, which has the above-mentioned connecting contacts.

As the main switch 1, the motor starter 10 has a solid-state contactor designed as a power semiconductor with a plurality of semiconductor switches, for example, implemented by triacs. The first connections of these semiconductor switches are connected to the corresponding (first) total power contacts L1 to L3 on the power source side of the motor-starter 10.

In addition, the motor starter 10 has an auxiliary switch 2, which is configured as a semiconductor switch, for example, as a triac, and is connected between auxiliary contact pairs 11 to 12 (open contacts; in this case, the auxiliary switch 2 operates as an open contact) or 13 to 14 (make contacts; in this case, the auxiliary switch 2 operates as a close contact) so as to interrupt or close signal lines connected to the auxiliary contact pairs 11 to 12 or 13 to 14.

In order to measure the currents of the three phases of the mains supply, the motor starter 10 has an electronic transducer unit 3, which electronic transducer unit 3 comprises, for example, a current transducer, a hall sensor or the like. At least one transducer is provided per phase, said transducer being dimensioned ten times the maximum allowable nominal current of the total current path.

The main switch 1 and the auxiliary switch 2 are controlled by an electronic control unit 4, said electronic control unit 4 being powered by the voltages applied at the control contacts a1 and a 2. The applied voltage is first fed to a rectifying circuit. The rectified output voltage of the rectification circuit is converted by a DC/DC converter into an operating voltage for the microcontroller and the driver circuit. The microcontroller μ C of the microcontroller and driver circuit executes firmware stored in its internal permanent memory, which configures the microcontroller μ C to process measurement signals of the transducers of the transducer unit 3 and to control the main switch 1 and the auxiliary switch 2 via the driver circuit based on the signals, as will be described further below.

The motor-starter 10 also has two further elements 5 and 6:

the parameterization unit 5 is provided and designed to assign the nominal motor current "Ir", the inert category "of overload release of the power supply of the motor, the behaviour" manual/automatic "(automatic or manual reactivation) after the overload release, as parameters of the electronic control unit 4. Manual reactivation is effected by means of a "reset" switch, i.e. after overload release and subsequent cooling phase, the motor can be restarted by means of the "reset" switch. The parameters "Ir" and "category" of the parameters "manual/automatic" of the cell 5 are adjusted by means of an actuation element configured as a rotary switch or potentiometer. The push button or toggle switch may be provided as a "reset" switch. The microcontroller μ C now monitors the motor while taking into account the parameters specified by the parameterization unit 5 and controls the main switch 1 accordingly, i.e. it activates or deactivates the semiconductor switches of the main switch 1.

The messaging unit 6 is controlled by the electronic control unit 4 and serves to signal the state of the motor starter optically and/or acoustically. Based on the measurement signals of the transducers of the transducer unit 3, the state is determined by the microcontroller μ C by simulating the motor warm-up using a model of the motor (temperature simulation). For an optical message, the unit 6 has a two-color LED, by means of which the status can be indicated as follows:

and (3) turning off the LED: no supply voltage is applied to the control connections a1 and a 2.

LED shining green: total switch 1 is activated, temperature simulation < 100%

The LED flashes red at 1 Hz: 100% < temperature simulation < 105%

The LED flashes red at 5 Hz: 105% < temperature simulation < 110%

LED shines red: temperature simulation < 110%, the main switch 1 is deactivated and the motor is in the cooling phase

LED flickers green at 1 Hz: the reactivation of the cooling phase of the motor from "reset" is completed after an overload, the control centre indicating "manual"

Another LED may be provided to indicate phase loss at the connected load:

and (3) turning off the LED: without phase interruption

LED yellow: phase failure

The motor-starter 10 may also have an interface (not depicted), by means of which process data can be read out from the motor-starter and transmitted to a control center. For example, current measurements, adjustment values, release causes, overloads/outages, etc. may be read and transmitted as process data. The interface may also be designed to receive data, for example parameters of the parameterization unit 5, and thus at least some of the parameters described above may be adjusted remotely.

From a data point of view, the interface can be implemented by a microcontroller μ C which can have additional modules for coupling the motor starter with a bus system, for example based on an Eaton Corp

The technology is either a fieldbus system according to the standard IEC 61158 or implemented by an industrial ethernet network. The microcontroller μ C may also be configured to host and send and receive data using multiple bus protocols.

Fig. 4 and 5 illustrate two embodiments of switches and transducers for the electronic dc motor starter 10.

Fig. 4 shows a main switch 1 with an auxiliary switch 2 and a transducer unit 3, by means of which all three current paths can be switched by connecting a triac 1' of the main switch 1 to each current path. In addition, a current transducer 3' of the transducer unit 3 is connected to each current path. The auxiliary switch 2 is implemented by a triac 2' connected between the auxiliary contact pairs 13 to 14.

Fig. 5 shows an implementation in which two of the three current paths are switchable by connecting one triac 1' of the main switch 1 to each of the current paths L1 to T1 and L3 to T3. Otherwise, this implementation corresponds to the implementation shown in fig. 4.

Fig. 2 shows a block diagram of a three-phase electronic reversible motor-starter 11, which differs from the motor-starter 10 shown in fig. 1 in that not only two but three control contacts (coil connections) a1 to A3 are provided and in addition a master switch suitable for the reversible motor-starter is used, such as the embodiment of the switch and transducer shown in fig. 3, wherein one triac 1 'of the master switch 1 is connected to each of the current paths L1 to T1 and L3 to T3, and one triac 1' of the master switch 1 is additionally connected between the master power contacts L1 to T3 and L3 to T1. In the embodiment shown in fig. 3, the auxiliary switch 2 also has two triacs 2' connected between two auxiliary contact pairs 13 to 14 and 23 to 24.

The motor-starter according to the invention has several advantages:

by combining two functions, "switching and protection", production and storage costs can be reduced. The electronics for controlling the semiconductor switches and the electronics for monitoring the current of the total current path may be combined to form an electronic unit.

The motor starter according to the present invention allows for reduced wiring costs. In addition, at least one additional auxiliary contact for deactivating the contactor in case of overload (e.g., opening contacts 95 to 96, closing contacts 97 to 98) may be omitted. Furthermore, no additional wiring for deactivating the contactor by the motor protection relay is required. Internal control electronics can replace additional auxiliary contacts and required external wiring. In the event of an overload, the electronics deactivate the semiconductor switching elements (main contacts and auxiliary switches open, closed).

In principle, the motor starter according to the invention allows the simulation of the motor temperature by means of internally deactivated contactors (semiconductor switches): the temperature simulation may be stored internally in the event that the motor starter is disconnected from the supply voltage. Thus, information of the simulated motor temperature is not lost and can also be taken into account after reactivation.

The motor starter according to the invention further allows to provide a supply voltage (motor protection function and switching function) connected via a DC/DC converter of the internal control electronics. This allows a cost-effective design of the measuring device (e.g. current transducer) of the motor starter, since it does not require a power supply of the consuming electronics, which would be the case if the motor protection relay were designed as a separate module with an external power supply.

A multi-voltage power supply may be inserted into a motor starter according to the present invention, thereby making it possible to construct a solid-state contactor with a supply voltage in the range of about 24 volts to about 240 volts, including a motor protection function. The cut-off limit is automatically determined based on the supply voltage applied at the control contacts a1, a2(, A3). Therefore, the voltage of the motor starter can be reduced from about four in total to a single voltage. The motor-starter according to the invention can also be designed with a plurality of voltages.

Claims

1. An electric motor starter (10) comprising

A main switch (1) configured as power semiconductor, the main switch (1) forming a semiconductor contactor and having at least one semiconductor switch for switching a phase of a total power supply of motor windings, wherein a first connection of each semiconductor switch is connected to a first total current contact (L1, L2, L3) on a corresponding power supply side of the motor starter (10),

an auxiliary switch (2) configured as a semiconductor switch and connected between at least one pair of auxiliary contacts (11, 12, 13, 14) of the motor starter, the auxiliary switch for interrupting or closing a signal line connected to the at least one pair of auxiliary contacts (11, 12, 13, 14),

an electronic transducer unit (3) for measuring the current of the phases of the mains supply, the electronic transducer unit (3) being connected between the second connection of each semiconductor switch of the mains switch (1) and a second mains supply contact (T1, T2, T3) on the corresponding load side of the motor-starter (10), and

-an electronic control unit (4) for the main switch (1) and the auxiliary switch (2), the electronic control unit (4) being supplied with power via control contacts (a1, a2) of the motor starter (10) and a measurement signal of the electronic transducer unit (3) being fed to the electronic control unit (4), and the electronic control unit (4) being configured to control the main switch (1) and/or the auxiliary switch (2) as a function of the power supply via the control contacts (a1, a2) and/or as a function of the measurement signal.

2. The motor starter of claim 1 wherein the motor is characterized by

It has a message transmission unit (6), said message transmission unit (6) being controlled by the electronic control unit (4) and being configured to generate messages about the state of the motor starter optically and/or acoustically.

3. Motor starter according to claim 1 or 2, characterised in that

It has an electronic parameterization unit (5), the electronic parameterization unit (5) being designed to specify at least one parameter for the electronic control unit (4).

4. The motor starter of claim 3 wherein the motor is characterized by

The electronic parameterization unit (5) is designed to specify at least one of the following parameters as a parameter for the electronic control unit (4): nominal current of the motor; an inactive class of overload release of the power supply of the motor; behavior after overload release.

5. The motor-starter of claim 4 wherein the action following the overload release is an automatic or manual reactivation.

6. The motor starter of claim 1 wherein the motor is characterized by

The electronic transducer unit (3) has a current transducer and/or a hall sensor and/or other suitable measuring means for measuring the current of the phases of the mains supply.

7. The motor starter of claim 1 wherein the motor is characterized by

The electronic control unit (4) is designed to adjust the nominal voltage rate of the motor-starter on the basis of the supply voltage applied at the control contacts (A1, A2).

8. The motor starter of claim 1 wherein the motor is characterized by

The master switch (1) configured as a power semiconductor has a plurality of semiconductor switches interconnected as a reversible starter.

9. The motor starter of claim 1 wherein the motor is characterized by

The main switch (1) configured as a power semiconductor is designed as a DC starter with semiconductor switches for at least one phase of the main power supply of the motor winding.

10. The motor starter of claim 9 wherein the motor is characterized by

The main switch (1) configured as a power semiconductor is designed as a DC starter with one semiconductor switch for each phase of the main supply of the motor winding.

11. The motor starter of claim 1 wherein the motor is characterized by

It has an interface by means of which process data are read out from the motor starter and transmitted to a control center and/or data can be received.

12. The motor starter of claim 11 wherein the starter further comprises a cover for the motor

The data are parameters for the electronic control unit (4).

13. The motor starter of claim 1 wherein the motor is characterized by

The electronic components (1, 2, 3, 4, 5, 6) of the motor starter (10) are arranged and wired together on a carrier element or on a plurality of carrier elements which are wired together.